The invention relates to a method for the production of packing bags which can be stacked on a wicket and can be unfolded while they are being filled, and for that purpose are provided on their bottom end with exposed wicket perforations. The bags are made from a web which first is folded over to form a channel-like half tube and is then folded together and bonded to make a folded tube. Such a method is disclosed in U.S. Pat. No. 4,669,251.
The procedure disclosed in the aforementioned patent is as follows:
(a) Before a web is folded over to form a channel-like half-tue, wicket perforations and notches are cut at regular intervals and at the same level, the position of a notch in relation to the adjacent wicket perforations situated at the same level being selected such that, in the film tube, the notch is situated above the wicket perforations and exposes them.
(b) The web is folded over, with the creation of gusset folds if desired, to make an open-sided tube.
(c) A longitudinal seam is made at the meeting edges of the open-sides tube and thus a folded tube is created.
(d) The folded tube is cut to lengths at regular intervals.
(e) Cross-seams are welded (sealed) to form open-ended packing bags.
This known method has the disadvantage that relatively large waste cutouts are made in the area of the wicket perforations and that the provision of a handle requires additional steps which raise the cost of the product.